Vegetation trimming devices are well known and are commonly used to maintain one's lawn and garden. There are a number of different classes of rotary trimmer heads, defined generally by the manner in which a monofilament trimmer line is fed, spooled or replaced in the trimmer head and/or how the trimmer line is discharged, indexed or lengthened during use of the trimmer head.
A first class of rotary trimmer head is the “self-indexing” trimmer head. With this type of trimmer head, a replaceable spool of trimmer line is used. These trimmer heads contain a mechanism to lock and unlock the relative rotation of the spool of trimmer line based on centrifugal forces which change the length of the line and allow for additional line to be released from the spool. As the line wears, there is less air drag and the rotational speed of the trimmer head increases. With the increased rotational speed, the mechanism unlocks the spool and additional trimmer line is released. The trimmer head speed then slows due to increased air drag on the longer length of trimmer line and the mechanism locks the spool. No manual feeding of new trimmer line is required. This trimmer head design undesirably limits the consumer's options regarding line selection.
A second class of rotary trimmer head is the “bump-fed” or “bump-activated” trimmer head. These trimmer heads are designed with a bump knob or similar ground contacting member that is mechanically linked to the internal spool in the rotary trimmer head such that both parts (the bump knob and the internal spool) have the same rotational speed. As with the self-indexing trimmer heads, the air drag helps to pull the line from the head. In addition, when the bump knob impacts the ground, the difference in rotational speed between the internal spool and the housing also helps push the line out. When the bump knob impacts the ground, the rotational speed of the knob and spool are slowed. The bumping action creates a vertical upward force which lifts the spool upward in the housing and briefly unlocks the spool from the housing so that the spool rotates independently. Some bump-fed trimmer heads are specific to the rotational direction of the trimmer device while others are “universal” and can be used with trimmers which rotate clockwise or counterclockwise. Because the indexing of the line is automatic upon striking the bump knob on the ground, control of the exact length of additional line that is indexed can be difficult.
A third class of rotary trimmer head is the “fixed-line” trimmer head. The majority of aftermarket trimmer heads for rotary trimmers that are sold are fixed-line trimmer heads because they are easily designed to be universally adaptable to essentially any brand of rotary trimmer regardless of the operation of the trimmer head or the direction of rotation. This type of trimmer head is loaded manually and eliminates the need for a spool. The head uses a base having a series of spaced line holders or an easy means of inserting, holding and/or removing multiple trimmer lines. As the line wears, the consumer manually inserts a new length of trimmer line into the line channel. There is no indexing or lengthening of the line during use; and, the consumer can control the length of line that is inserted. Unfortunately, when trimmer line strikes solid objects such as rocks and wooden or metal fences, which is common during use, the trimmer line tends to break thus requiring the consumer to remove the broken line and re-load fresh line quite often.
Incorporating pivoting technology into fixed-line trimmer heads is proving to be beneficial to increasing the life of trimmer line. U.S. Pat. Nos. 7,603,782 and 7,743,511 by Orlando Jerez disclose a trimmer head with pivoting line holding mechanisms, hereby incorporated by reference. The invention disclosed by Orlando Jerez includes many means of holding a folded strip of line. However, all of the concepts introduced by Jerez involve a line holding means located on the top of the trimmer head. The trimmer line is loaded into the line-holding mechanism in the limited space defined by the lower surface of the debris shield on the trimmer, the upper surface of the trimmer head, and the gearbox and/or hub of the trimmer head. Additionally, there is no means provided to assist with removing the used strip of line from the line holding mechanism. During use, the folded strip of line is pulled tightly into the straight through line channels. Many consumers report the need to use a pair of needle nose pliers to pinch the backend of the folded line to remove the U-shaped portion of the used trimmer line.
One of the objectives of this invention is to provide a novel trimmer head with pivoting line-holding mechanisms that can be loaded from the ground-facing surface of the trimmer head.
Another objective of this invention is to provide a novel trimmer head with a means to push a U-shaped piece of trimmer line partially out of the pivoting line-holding mechanism for the purpose of facilitating removal of the remaining line after use.
A third objective of this invention is to provide a method for removal of the unused portion of a trimmer line remaining in the line holder after use of the line for trimming vegetations.